Now this is an evil Prime. I like how they didn't just do a straight Sourge/Nemesis Prime-style redeco. This looks more like a contaminated/infected Prime. In fact, if one wanted to, he could be nicknamed "Virus Prime".

He does look pretty wicked. My best guess is that they're going for the "Dark Awakening" look Optimus had back in G1 when he miraculously had come back to life, but with cracks and a good amount of battle damage. For younger fans that may not know the epi., basically Optimus was brought back to life by Quintessions, and programmed to destroy the Autobots.

I wonder if they'll even be called "Decepticons" because of the "Deception" part of their name. "Autobots" doesn't need to be changed because it only refers to "Automobile" which could be for good or evil. But if they can come up with a clever name change for "Decepticon" then that would be interesting.